A study is proposed to explore the information-seeking behavior of cancer patients and their families. Subjects for the study will be a sample of cancer patients and their relatives who call the Cancer Information System (CIS) and a comparison sample of patients, selected from the Illinois Cancer Registry and matched on demographic, source of care, and disease characteristics. Data will be collected through follow-up interviews of the CIS callers and from interviews of the patients in the matched sampled to determine: 1) the information needs and information- seeking activities of the patients or their families; 2) when information is obtained, whether it is communicated to current physician; and 3) whether such information has any impact on subsequent cancer care decisions. The specific goals of the study are to: 1) determine the extent to which diffusion of cancer information occurs through utilization of the CIS by cancer patients, and through the patients then communicating that information to their physicians; and 2) determine why diagnosed cancer patients seeks information beyond that obtainable from their physicians, what sources they contact, how they use the information so obtained, and whether these activities are peculiar to CIS callers or generalizable to other cancer patients. These results will be used to develop a model of cancer patient information-seeking behavior and of how such behavior fits within patient-physician relationships.